What I have been toiling myself with is Dungeon and Dragons online power leveling of Svegrund. I am taking him through barbarian past lives for the extra hit points on future lives. I have got to say you are not going wrong with barbarian lives. The beginning quests were way easier with just one barb past life. Its just a help to everything unlike my bard lives.
So far I have learned, get in a group that have a goal planned. I don't care if the depths are less experience than derping from quest to quest, they can be run in a half hour bang, bang , bang. Knowing what you are doing getting your ship buffs once and running is so much better than waiting for one dude who is dicking around to smoke and take a bio. Just trying to decide what to do that kills! Figure out if your group is free to play and what packs they have. From there go with the lowest common denominator and run quests near your level. Just run!
I am no expert but here are a few quests I have power run so far. Stealthy repossession, The Kobold's New Ringleader, Tome of the Immortal Heart, Tear, Gwylans, Running with the devils. Any of those are good with a group of determined folks. You just need to know if you are zerging or not because that is an all or nothing activity. I am new to the zerg and get yelled at all the time, but I am trying to be open and listen to folks.
Also you don't need to fully sandbag in fact i think that is a poor idea. You should probably think of getting 4 into the next level and then taking it. You don't want to limit a group that is going like rolling thunder and have them wait for you to level. Sure there are times when you have no choice but letting everyone know is good. Synchronize your Bio's and drink with leveling. You don't get a drink you are leveling you go without, just pee and ship buff and don't waste the groups time more.